To examine the occurence rates of adverse reactions, the response rates of MEDI-500 to determine the pharmokinetics. To examine the development of human anti-mouse antibodies after administration of the drug. To examine the effect on circulating lymphocytes and their expressed receptors, on serum levels of selected cytokines and urinary levels of selected enzymes, the incidence of posi tive skin prick tests to MEDI-500 and to examine the impact of the rate of infusion of the first dose on the occurence of adverse reactions.